1. Field of the Invention
This invention relates to block copolymers of polyphenylene oxides and polyformals of non-sterically-hindered dihydric phenols. These block copolymers can be molded, calendered, or extruded as films, sheets, fibers, laminates or other useful articles of manufacture.
2. Description of the Prior Art
Polyphenylene oxides having an average hydroxyl group per molecule of 1.0 or less are described in A. S. Hay's U.S. Pat. Nos. 3,306,879; 3,914,266; and 4,028,341; among others.
Polyphenylene oxides having an average hydroxyl group per molecule greater than zero including 2.0 or less are described in D. M. White's U.S. Pat. Nos. 4,140,675 and 4,234,706 are among others.
Polyformals are described in R. Barclay, Jr.'s U.S. Pat. No. 3,069,386, A. S. Hay's copending U.S. Ser. No. 858,040, filed Nov. 6, 1978, now U.S. Pat. No. 4,134,734, and G. R. Loucks et al., U.S. Ser. No. 889,397, filed Mar. 23, 1978 now U.S. Pat. No. 4,260,733.